merges r22987 from trunk into ruby_1_9_1.

--
* lib/pathname.rb (Pathname#sub): set $~ in block.binding.
  [ruby-dev:38173]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_9_1@23217 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,8 @@
+Tue Mar 17 14:25:16 2009  Tanaka Akira  <akr@fsij.org>
+
+	* lib/pathname.rb (Pathname#sub): set $~ in block.binding.
+	  [ruby-dev:38173]
+
 Sun Mar 15 02:09:31 2009  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* proc.c (bmcall): should not uninitialized variable.  a patch from

lib/pathname.rb

@@ -251,7 +251,21 @@ class Pathname
 
   # Return a pathname which is substituted by String#sub.
   def sub(pattern, *rest, &block)
-    self.class.new(@path.sub(pattern, *rest, &block))
+    if block
+      path = @path.sub(pattern, *rest) {|*args|
+        begin
+          old = Thread.current[:pathname_sub_matchdata]
+          Thread.current[:pathname_sub_matchdata] = $~
+          eval("$~ = Thread.current[:pathname_sub_matchdata]", block.binding)
+        ensure
+          Thread.current[:pathname_sub_matchdata] = old
+        end
+        yield *args
+      }
+    else
+      path = @path.sub(pattern, *rest)
+    end
+    self.class.new(path)
   end
 
   if File::ALT_SEPARATOR

test/pathname/test_pathname.rb

@@ -392,6 +392,15 @@ class TestPathname < Test::Unit::TestCase
   defassert(:pathsubext, 'fooaa.o', 'fooaa', '.o')
   defassert(:pathsubext, 'd.e/aa.o', 'd.e/aa', '.o')
 
+  def test_sub_matchdata
+    result = Pathname("abc.gif").sub(/\..*/) {
+      assert_not_nil($~)
+      assert_equal(".gif", $~[0])
+      ".png"
+    }
+    assert_equal("abc.png", result.to_s)
+  end
+
   def root?(path)
     Pathname.new(path).root?
   end